Test & Measurement

Conformity assessment: The safe path to a successful C-V2X roll out

2nd December 2019
Mick Elliott

Over the past decades the introduction of seat belts, airbags, and vehicle crumple zones have made a massive contribution to saving lives on our roads, writes Holger Rosier of Rohde & Schwarz. Today’s advanced driver-assistance systems (ADAS) and future autonomous driving solutions will go some way to further driving down the number of incidents on our highways, but they remain limited in their impact without access to the collective insights of all road users.

Even the most focused driver cannot react to an incident happening directly in front of him or obscured behind a blind bend. But, collectively, our companions on the road, drivers, cyclists and pedestrians, could share such insights with one another, allowing us to react accordingly and in time. This is the vision that vehicle-to-x (V2X) communication offers the road users of tomorrow.

Like all technologies, it requires standards to ensure that everyone approaches the implementation in the same manner. However, who will be there to ensure the standards are met? And are there historical parallels that can provide us with suitable approaches?

Key to ensuring that automated and cooperative driving become reality and that the systems developed by different car manufactures and their suppliers are interoperable are standards.

Those for V2X communication are defined in a wide range of documents that cover everything from the radio access technologies up through to the facilities and applications layers.

Worldwide communication layer standard

Across the world, various standards for intelligent transport systems (ITS) have been developed. These range from the Wireless Access in Vehicular Environments (WAVE) in the US as defined in standards family IEEE 1609, and ETSI ITS-G5 in Europe.

Both of these can be based upon IEEE 802.11p, an extension of the WLAN standard. The 3rd Generation Partnership Project (3GPP) have worked, in parallel, on a worldwide communication layer standard that also enables ITS to operate over cellular network technologies, exploiting existing commercial mobile network technology.

The device-to-device (D2D) communication over this technology does not require any mobile network infrastructure. The initial provisions, first introduced in standard Release 12 in 2015, were further refined to support the needs of cellular vehicle-to-everything (C-V2X) communication with 3GPP Release 14 in 2017, referred to as LTE V2X.

In fact, the Internet-of-vehicles (IoV) as currently being implemented China utilizes standards developed by several bodies, including the Society of Automotive Engineers of China (SAE-C), together with C-V2X.

Considered as a whole, C-V2X is an excellent technology for all road users, from pedestrian to powered, to share messages on the status of vehicles and our highways, with traffic infrastructure while at the same time providing access to internet and cloud services.

Because it is built upon the ubiquitous 4G LTE cellular technology already in use today, and because the 3GPP standards include a roadmap to the increased bandwidth and reduced latencies of future 5G networks, future compatibility is already built in.

Furthermore, the necessary chipsets for radio communication and test equipment for proving interoperability are already in general circulation.

4G LTE test standards prevail

Here, an important distinction about C-V2X needs to be made. For the foreseeable future, a lot of the communication will be based upon 4G LTE. 5G support is around the corner and, as the network infrastructure is rolled out, some cellular vehicle-to-network (C-V2N) communications are likely to transition to 5G. However, all other V2X functionality, such as vehicle-to-pedestrian (V2P), vehicle-to-vehicle (V2V), and vehicle-to-infrastructure (V2I), will continue to require testing and approval against the existing 4G LTE standards for the foreseeable future.

What is also highlighted by the process that has created C-V2X is the tremendous amount of collaboration required to develop such standards.

Some of the work has been supported by government grants for research into how best to approach the challenges of an ITS solution.

Organisations such as 3GPP also have their roots in collaboration, ensuring that cellular handsets can operate globally. And now, to ensure that the automotive industry and the radio technology upon which C-V2X will rely meets everyone’s needs, a new organization has been formed.

The 5G Automotive Association (5GAA) is a cross-industry group of key automotive players and representatives from the telecommunications industry. Since its inception it has established a global footprint of key industry representatives who ensure that the necessary next stage of integration of automotive solutions with telecommunications technology moves forward smoothly.

Their working groups examine a wide range of issues, from high-level topics such as business models and go-to-market strategies, to technical requirements and system architecture.

They also undertake evaluations and promote large-scale trials, ensuring that technical concepts have the opportunity to be tested in the cold reality of our highways.

This has resulted in a series of comprehensive white papers and studies providing in-depth insights into the technology underlying C-V2X.

Software is a differentiating factor

Testing is an essential element for the launch of any product, and it accompanies the product from the research and development laboratory right through to end-of-line testing after manufacture. Obviously, one element of testing is to ensure that the equipment operates within the limits as defined by the standards.

For a telecommunications device this includes the RF stage along with the device’s support for the various protocols it is designed to support. Rohde & Schwarz is well positioned with its test solutions to provide support in this area.

Over the years it is the software, and its ability to quickly and easily configure hardware test equipment to test a wide array end equipment, that has become a key differentiating factor.

The interaction of a single C-V2X solution in conjunction with a reference system as defined by test equipment is, for sure, an essential benchmark test to have undertaken. However, there still remains the issue of interoperability. The worldwide success of the radio telecommunication standards developed by 3GPP can be assigned, in part, to the harmonised testing processes that take place.

The Global Certification Forum (GCF) has established itself as the de facto arbitrator for conformity with the standards. The first stage entails testing handsets and modems independently for conformance with the relevant radio frequency and protocol standards. The second stage involves evaluation of the handsets as part of an operator carrier acceptance test.

This includes undertaking performance benchmarking and proving that various network functions operate as expected.

With the automobile essentially becoming connected and expected to operate seamlessly with other mobile nodes across national and international boundaries, consideration for such a testing procedure of C-V2X components and Electronic Control Units (ECUs) should surely also be undertaken.

The 5GAA is working to promote such a harmonized testing program for C-V2X conformity assessment. As for the telecommunications industry this could be split into conformance testing for the specific communication protocol layers and interoperability testing applied to the final end device.

Such an approach includes harmonized test procedures, a set of minimum requirements, and selection of suitable test partners. The radio access layers would necessarily require conformance with the worldwide 3GPP standard, while the upper application related layers would be tested against regional standards, most likely split into EU, US and China regions.

C-V2X has the potential to significantly improve safety for pedestrians and transportation solutions alike. The participation of Rohde & Schwarz in the standards organizations, boards, panels and advisory committees that contribute to the necessary technologies is indicative of our vision for achieving zero accidents on our roads and highways.

As ITS and C-V2X move from concept to reality, we will continue to use our unique insights, learning and experience to bridge the worlds of the automotive and telecommunication industries to the benefit of all road users.

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